Black triangles: deceleration of the spin rate since rendezvous with comet 67 P as a function of time from August 2014 to 6 May 2015. Bottom scale: day of year 2015. Top scale: days before 2015 perihelion. They were time-derived from ESOC data of Fig. 2, obtained by the ESOC navigation team from the fit of observed landmarks with a shape model and an assumed constant spin rate over a period of a few days. The strong oscillations with a period of 16 days are most likely not real and linked to the simplifying assumption of no precession (see text). The thick gray line is a smoothed average over 32 days. It shows that the spin rate change went through a minimum around April 10 and changed sign around mid-May 2015, a sign of outgassing pattern change linked to the solar illumination geometry change, passing to more southern latitudes.